Gray was diagnosed with right pectoral soreness after leaving Sunday's start against Kansas City, Phil Miller of the Minneapolis Star Tribune reports.
The veteran right-hander fired six scoreless innings before suffering the injury during the seventh inning, and the one runner he left on base was allowed to score by the bullpen. Gray remains in line to pick up his third straight win, but his health is obviously the more pressing concern. The severity of the injury remains unclear, leaving Gray's availability in question going forward. He's expected to undergo an MRI later Sunday or Monday, according to the Associated Press.